(1) Field of the Invention
The present invention relates to a tracker touch apparatus for use with a keyboard having a plurality of selectively depressed keys. In particular, the present invention relates to a magnetic tracker touch apparatus employed with the keyboard of a musical instrument. The apparatus magnetically resists the depression of keys of the keyboard and thereby simulates in keyboard keys of an electrically operated musical instrument the feel of keyboard keys of a mechanically operated musical instrument.
(2) Description of the Related Art
In prior art mechanically operated organs such as pipe organs, the keys of the organ keyboard have a certain "feel" to the organist depressing the keys. The particular "feel" of pipe organ keys is primarily due to the mechanical connection of the keys to valves of the organ that control the selective supply of pressurized air to organ pipes actuated by the keys. With the keyboard keys in their at rest position, the valves disrupt communication between the source of pressurized air and the organ pipes and air pressure backs up behind the valves. By depressing a keyboard key, the valve mechanically connected to the key is moved against the backed up air pressure to a position where it no longer disrupts communication between the air pressure and the organ pipe operated by the valve. As the valve initially moves to communicate the source of air pressure with the organ pipe, it must first overcome the air pressure backed up against the valve. This gives the organist a particular "feel" of resistance to depression as the organ key is first depressed. As the organ key is further depressed, the valve operated by the key overcomes the initial resistance of the backed up air pressure and permits communication between the air pressure source and the organpipe operated by the valve. The overall result is a feeling of initial resistance to depression of the key, and then a noticeable reduction in resistance as the key is depressed further downward. The "feel" in the keys of initial resistance to depression, and then release of the resistance after initial depression is preferred by many keyboard musicians.
In prior art keyboard musical instruments that are operated electronically and do not employ the mechanical connections between the keyboard keys and pipe organ valves, depression of the keyboard keys does not have the "feel" associated with prior art musical instruments having mechanical connections between the keyboard keys and pipe organ valves. In prior art musical instruments of this type, tracker touch systems have been employed to simulate the "feel" of keyboard keys mechanically connected to pipe organ valves. Prior art tracker touch systems have been known to employ coil springs and leaf springs in a variety of arrangements to simulate the desired "feel" of prior art mechanical keyboards. Examples of these types of tracker touch systems are disclosed in U.S. Pat. No. 3,680,426 and No. 4,479,415.
Disadvantages often encountered with these prior art tracker touch systems include the failure of the coil and leaf springs after a period of time. With repeated use of these prior art systems, the coil and leaf springs employed often lose some of their resiliency. As a result, the resistance to depression that produces the desired "feel" of the keyboard keys is lessened, in some cases to the extent where the key offers no resistance at all to depression. In some cases the coil or leaf springs will fail completely by breaking after repeated use over a period of time.
It is an object of the present invention to provide a unique tracker touch apparatus that produces a desirable "feel" when depressing keyboard keys without relying on leaf springs or coil springs.
It is a further object of the present invention to provide a tracker touch apparatus that requires no external source of power.
It is a further object of the present invention to provide a tracker touch apparatus that is adjustable so that the magnitude of the resistance to depression of the keyboard keys caused by the tracker touch apparatus can be adjusted to a desired magnitude.
It is a further object of the present invention to provide a tracker touch apparatus that employs no moving parts and is therefore not subject to wear or fatigue failure over a period of use.